Seat post cluster structure for bicycles



.Dec, 13, 1949 I L. KRAEFT ET AL SEAT POST CLUSTER STRUCTURE FOR BICYCLES 2 Sheets-Sheet 1 Filed March 12, 1947 INVENTOR. HEEMAI/ L. may?" BY LEONARD .1 ML7'E28 ATTORNEYS 1949 H.YL. KRAEFT ETAL 2,491,379

S'EAT POST CLUSTER STRUCTURE FOR B'ICYCLES Filed March 12, 1947 2 Sheets-Sheet 2 INVENTORSL HERMAN L KMEFT LfOVARD J WAL T638 1 7%, MM; 9 a

Patented Dec. 13, 1949 SEAT POST CLUSTER STRUCTURE FOR BICYCLES Herman L. Kraeft, Cleveland Heights, and

Leonard J. Walters, Shaker Heights, Ohio, assignors to The Murray-Ohio Manufacturing Company, Cleveland, Ohio, a corporation of Ohio Application March 12,1947, Serial No. 734,120

This invention is directed to a seat post cluster structure for bicycle frames and a method of forming the same and comprises an improvement over the structure shown in our prior application Serial No. 576,932, filed Feb. 19, 1945, now Patent N0.2,443,008. I

In our prior application we have disclosed a method of constructing a bicycle frame by having the various reach bars or tubular sections preassembled in a press fitted manner whereby all of the tubular joints of the frame may be copper brazed simultaneously by passing the same through a hydrogen furnace, The present invention is concerned with the obtaining of a more rigid pre-assembly of the tubular ends joined with the seat post mast tube whereby the preassembled relation of all ofthe tubular members comprising the frame will be maintained accurately when the entire frame is subjected to the comparatively high temperatures necessary to effect an efficient copper brazing of the joints. This cluster structure is such that during the final preassembly of the entire frame'it exerts a final locking action which prevents any relative creeping or slipping of the several tubular sections comprising the frame during such a brazing operation. In our prior patent we proposed to form a branched cluster member or bracket, the branches of which were formed to receive the ends of the upper forward reach bar and the ends of the upper rear fork members. While such a structure, with due care in making, proved to be satisfactory, nevertheless, inaccuracies and variation in production at times inr troduced uncertainties which we have eliminated by the present disclosed structure and method of final formation thereof.

The general object of the present invention accordingly is to provide an improved tubular joint comprising the seat post cluster structure of a copper brazed bicycle frame which will be sufficiently rigid and accurate in preassembled condition and during the brazing operation to maintain the frame members in proper position when subjected to from 1980 to 2020" F.

A further object of the present invention is the provision of a seat post cluster structure for a bicycle frame which can be made by the copper brazing method and which will have inherent I 4 Claims, (Cl. 287-54) being made to the accompanying drawings wherein;

Fig. 1 is a view in elevation of a bicycle frame, certain parts being broken away to show the interior thereof;

Fig. 2 is a view in section of the seat post structure of the frame, the view being on a larger scale cycle such as that indicated at ID in the drawings. The frame consists of a lower reach bar ll connected at one end to a tubular housing l2 and at the opposite end to a hangar housing I 3, the housing l2 being adapted to support the front wheel structure of the bicycle and the housmg I 3 forming a journal for the sprocket bearing. A seat post reach bar I4 extends upwardly from the housing l3 and a top reach bar l5 interconnects the bar l4 with the housing I2. A second upper reach bar l6 interconnects the reach bar l4 and bar II. A pair of rear yokes l8 are supported by a lower fork member [9 and an upper fork member 20, which members are connected to the yokes l8 and to the housing I3 and bar M, respectively. The rear wheel of the bicycle is mounted to the rear yokes. A preferred method of forming the frame I!) is to assemble the various bars and housings in the form shown by interconnecting the various frame members with more or less press fits and with brazing metal located adjacent to the junctures of the'members. This assembly is referred to as -a preassembly, and then the entire preassembled frame is placed in a hydrogen furnace where the temperature of the frame is brought up to that at .which the brazing metal will melt and flow between the abutting surfaces of the various frame members so that when the frame is removed from the furnace, the brazing metal on gether at the seat post assembly, which is indicated generally at 24, and it is essential that this portion of the frame structure be rigidly connected in the preassembly.

Our inventionlis directed toar improved seat post stfiirture andniethod of? forming the same whereby the requisite preassembled rigidity is provided and which structure may be readily assembled with a minimum of simple elements;

Referring more particularly 'toi-tliefistructure shown in Figs. 2 and 3, a sheath-like seat post recelving member 25 is telescoped;into;;the,.upper end of the reach bar [4. The member fiimaybe; formed of a sheet metal: stamping ;f:oldeda=in .a tubular form. The stampingmis-made; with two:

cars or lugs at one end and on opposite sides so of which is shown at 25, willx'tendpa'rallel'and adjacent to one another for receiving aclamping w and two similar radiallyextendingtapered bores 3i and 32 apedrilled through the collar, bar l4 and sheath 25 for recei'vin'g the two branches 33 '1 nd 34,-resp ectively, of: the rear fort: 2B. The an; and sheath 2 5 have a tapered opening 35 4 each, bar it. {The-ends of the reach bars and and thezbranches 33 and Share swagedgas is d atedbyfthe broken lines 36 so that these mbersrnay be easily inserted into the tapered the openings ;for. forming a tight press fit jg'therewithg preferably having a clearanceof beftweenaow and .0 05. The terminal parts of the s gmendser the tubes l5, l 5, 33 =and 4 rna be straight: and the complementary or re- ;jc 'vmgbores, straight and with the minusiclearances specified; Preferably, the reach bars 15 nd' lt and the branches 33-and 34 are provided reinforcing members s'l which members are provided with grooves for receiving rings of, braz- "mg metal 38. Inthe preassembly of. the frame the seat ,post structure, is assembled last, and it will be understood that thecollar 21 W111 be placed 10 ,bar 'lldfprior to the telescoping of sheath -25 ji'ntob'ar l4. Thecollar 21 may fit snugly-to the "instances, the

a e members l5 and 34 respectively-and pins {and are driven into theseopenings whereb the ,frame" members are mechanically locked the'reachbar I 4., o 1

efo're theirame is, placed in the brazing fur- :rings qffc'opperare placed about the, upper .Offthe .ba 14 a d b u t e upiqe l d f 7 1221. These rings are shown in broken lines f t 4 am ,45, respectively.,, The ,framefis then placed in the furnace and heated to the proper 1 ed therein for the reception of theend' or s t- 30, 3 l, 32 and- 35-, respectively, and 'wedgedr lfil alndtheppenings 30, 3| and 32 are drilled I0 the nds 'oiathejframe members 15, I6, 33 and 34.

Likewise, the metal from ring will flow bewiden the abutting surfaces of the collar 21 and 4%and between' the walls of the openings 38, v nd' 32-; andz the abutting surfaces of the remem framewmembers. When the frame is cooled the brazingymetal will have formed a firm bond between the members comprising the seat poststructurej"andby proper selection of the size oj the'rings 44 and 45, little, if any, brazing metal 20 will be present on the: exterior of the structure;- IIhis eliminates the necessity of cleaning of the istrllitliief'oi 'eXoeSs' metal, and a clean appearbe i he" final structure is inherent. By raz'ing thelend of bar 16 into the opening 35,, thehbarglfilfis"fliinlylsecured in lace and its os'ition' is'positivelymaintained during theheat- ,o.f.the ram A'ftef thebrazing operation the inner ends of the; ars l 5j and 16 and the branches 33 and tb eme .w thth lpi s; 39 and dmmay b rem by'ifrisje'rtir'ig'a'drillfinto the seat post sheath 25 fee that the sheath will be clear to receive the seat "iltfwill' e apparent "that by our invention the fbar I 5f'and",forkfmember 2U willbe rigidly atftachedtdthe reachbar I4 by a strong connection and theiparts for effecting this connection are ffewi 'an'd easily-formed so, that extreme care and time is not n'ecessary'for obtaining a sturdy and 'r-r' t appearingstructure. w is to b under st'ood that although I we have fdescribed -but one form 0f the invention; other foi ms-mighfibe'used, all falling within the scope -othes-claims which follow I Werclaim: V I lz FAsseatnpost :cluster structurefor -a bicycle frame comprising a seat postmasttuba a tube- -like seat -post sheath telescoped into the upper 15nd -T0f the" seat post ma'st; a reinforcing collar on 'the outside 0f=and embracing the upperportion i'of'the tubular mast at the cluster structure, said coll'ar,--mast and sheath having two independently formed; openings extending therethrough for the receptionof-tubular upper rearfork ends and a 65 generally opposite-similar opening formed for the IEQEBtiODgflf an end of a frontupper reach bar tube, upper- -rearfork-tubeshaving ends independently extending into thefork tube openings ofthecollar and.- the =-rnast and the sheath and a reach bar tube end extending into the other opening of the collar:and the mast and'the sheath wherebyall of said tube-ends are connected to the walls of. the sheath, themast and-:the collar 'ganq a copp'er brazed connection formedbetween all lof, the contacting surfaces of said tubeends and'said three members. 1 I 2. A seat postfcluster structure for a bicycle :frameccomprising .eat pest mast tube, a tubel ilce'f seat post sheath telescoped intov thegupper 7 end of the seat post mast, a reinforcing collar on the outside of andembracing the upper portion of the'tubular mast at the cluster, said. flcollar, ;I na st ar1d sheath having tapered openings extend- .l'ng', tlirethrough-for the reception-of a tubular 75 upper r'e'ar fork structure and for the reception of an end of a front upper reach bar tube, tapered tube ends extending into said tapered openings whereby the tapered tube ends are in a wedged connecting relation to the collar and the mast and the sheath and a copper brazed connection formed between all of the contacting surfaces of said tube ends and said three members and between the contacting surfaces of the three members relative to each other.

3. A seat post cluster structure for a bicycle frame comprising a seat post mast tube, a tubelike seat post sheath telescoped into the upper end of the seat post mast, a reinforcing collar on the outside of and embracing the upper portion of the tubular mast at the cluster structure, said collar, mast and sheath having two independently formed openings extending therethrough for the reception of tubular upper rear fork ends and a generally opposite similar opening formed for the reception of an end of a front upper reach bar tube and all of said openings being tapered, upper rear fork tubes having tapered ends independently extending into the tapered fork tube openings of the collar and the mast and the sheath and a tapered reach bar tube end extending into the other opening of the collar and the mast and the sheath whereby all of said tube ends are connected to the walls of the sheath, the mast and the collar and a copper brazed connection formed between all of the contacting surfaces of said tube ends and said three members.

4. A seat post cluster structure for a bicycle frame comprising a seat post mast tube, a tubelike seat post sheath telescoped into the upper end of the seat post mast, a reinforcing collar on the outside of and embracing the upper portion of the tubular mast at the cluster, said collar, mast and sheath having two independently formed openings extending therethrough for the reception of tubular upper rear fork ends and a generally opposite similar opening formed for the reception of an end of a front upper reach bar tube, said sheath extending downwardly within the mast a considerable distance below said three openings, upper rear fork tubes having ends independently extending into the fork tube openings of the collar and the mast and the sheath, an upper front reach bar tube end extending into the other opening of the collar and the mast and the sheath and a second front reach bar tube having an end thereof extending through an opening formed in the mast and sheath walls below the cluster structure whereby all of the top tube ends are connected to the walls of the sheath, the mast and the collar and the fourth tube end is connected to the sheath and mast walls and a copper brazed connection formed between all of the contacting surfaces of said tube ends and the mast and sheath structures.

HERMAN L. KRAEFT. LEONARD J. WALTERS.

REFERENCES CITED The following references are of record in the OTHER REFERENCES Schmidt Copper Furnace Brazed Parts and Principles of Design Product Engineering, October 1946, pp. 103-107. Copy in 113-112 Lit.

DeDomenico How Brazing Methods Affect Design of Details Product Engineering, April 1948, pp. 86-91. Copy in 113- 112 Lit.

Tylecate The Mechanical Properties and Some Metallurgical Features of Copper Brazed Joints Welding Journal, April 1946, pp. 242-248. Copy in 113412 Lit. 

